A heart sound, which results from the movement of a heart, includes high-frequency components caused by blood pressure. It is known that the heart sound has strong correlation with the blood pressure, and it is possible to estimate the blood pressure by suitably processing heart sound data using a computer.
Patent document 1 discloses the technical content of a central blood pressure measuring device that measures the central blood pressure based on the heart sound.
Patent document 2 discloses the content of a technique for removing noise components while detecting the heartbeat.